Which medicines are used to treat hypertension?

• ACE inhibitors stop the production of a hormone called angiotensin II that makes the blood vessels narrow. As a result, the vessels expand, improving blood flow. Tension in the circulation is also lowered by the kidneys filtering more fluid from the blood vessels into urine. This also helps reduce blood pressure. If your blood pressure is not easily controlled on simple medication, your doctor will probably use a medicine of this type.
• Angiotensin-II receptor antagonists work in a similar way to ACE inhibitors. But instead of stopping the production of angiotensin II, they block its action. This allows the blood vessels to expand, improving blood flow and reducing blood pressure.
• Beta-blockers block the effect of the hormone adrenaline and the sympathetic nervous system on the body. This relaxes the heart so that it beats more slowly, lowering the blood pressure.
• Alpha-blockers cause the blood vessels to relax and widen. Combining them with beta-blockers has a greater effect on the resistance in the circulation.
• Calcium-channel blockers reduce muscle tension in the arteries, expanding them and creating more room for the blood flow. In addition, they slightly relax the heart muscle so it beats more slowly, reducing blood pressure.
• Diuretics help the body get rid of excess salt and fluids via the kidneys. In certain cases, they relax blood vessels, reducing the strain on your circulation.

The following medicines are used less frequently.

• Indapamide (eg Natrilix) is a mildly diuretic preparation that also relaxes the peripheral arteries.
• Hydralazine (eg Apresoline) relaxes the vascular walls in the peripheral arteries thereby reducing the blood pressure.
• Methyldopa (eg Aldomet) stimulates the alpha receptors in the brain that relax the blood vessels, causing the blood pressure to drop.
• Moxonidine (eg Physiotens) is another medicine that acts on receptors in the involuntary part of the brain, causing blood pressure to decrease.
• Minoxidil (Loniten) relaxes the small arteries so that blood pressure drops. It must be used in combination with other hypertension medicines.